Diabetes Flashcards
What is the mechanism for type I diabetes mellitus (DM)?
Insulin deficiency
What is the mechanism for type II DM?
Insulin resistance
What are the main differences between type I and II DM in terms of age of onset, autoimmunity, body habitus, and risk for ketosis?
Which autoantibodies can be positive in type I DM?
- Anti-islet cell
- antiglutamic acid dehydrogenase antibodies
Does the absence of autoantibodies rule out the diagnosis of type I DM?
- No.
- Some patients with type I DM do not have autoantibodies, and
- some with type II DM do.
What are some classic presenting symptoms of DM?
- Polyuria
- polydipsia
- unexplained weight loss
- blurry vision
How do you diagnose diabetes?
What do you do after an abnormal test?
- Confirm the diagnosis on a subsequent day by using FBG, OGTT, or HbA1c. Patients with glucose ≥200 mg/dL and classic symptoms do not need repeat testing.
What is prediabetes?
- Impaired fasting glucose and/or impaired glucose tolerance
What is the clinical implications of prediabetes ?
- Patients with prediabetes have an increased risk for future development of diabetes mellitus and macrovascular disease.
- They have a 50% increased risk for myocardial infarction or stroke.
What behavior changes should you encourage in a patient with prediabetes?
- Smoking cessation
- weight loss (5%-10%)
- diet changes
- exercise (30 minutes per day, five times per week)
Why is it important to identify patients with prediabetes?
- Lifestyle modifications can delay and even prevent progression to diabetes.
What are the three main microvascular complicaitons of diabetes?
- Retinopathy
- Nephropathy
- Neuropathy
What are the three main macrovascular complications of diabetes?
- Atherosclerosis
- Cerebrovascular disease
- Peripheral vascular disease
How frequently should diabetics be seen by an ophthalmologist?
- annually
What is the incidence of retinopathy in patients who have had type II DM for 20 years?
50%-80%
What is usually the first sign of diabetic kidney damage?
Microalbuminuria
What medication can help reduce the risk of diabetic nephropathy?
Angiotensin-converting enzyme inhibitors or angiotension II receptor blockers
What are the different types of diabetic neuropathies?
- Peripheral, autonomic, mononeuropathy (eg, cranial nerve palsy)
Describe the manifestations of diabetic peripheral neuropathy?
- Symmetric sensory dysfunction
- distal sensory loss
- paresthesias
How do you test for diabetic peripheral neuropathy?
- Place a monofilament at a right angle to the plantar surface of the skin of the foot.
- Increase the pressure until the monofilament buckles.
- Ask the patient whether or not he/she felt the pressure from the filament.
How should diabetics care for their feet?
- Inspect feet daily for skin cracks and signs of infection between the toes
- avoid walking barefoot
- ensure shoes fit appropriately.
What should you look for when examining the feet of diabetics?
- Skin breaks
- early ulcers
- decreased pedal pulses
- delayed capillary refill
- bony deformities
Describe manifestations of autonomic neuropathy
- Gastroparesis
- orthostatic hypotension
- impotence
- neurogenic bladder
What interventions did the UK Prospective Diabetes Study compare?
Four thousand type II diabetics were assigned to either intensive therapy (sulfonylurea, metformin, and/or insulin) or diet alone.
What did the UK Prospective Diabetes Study show?
- Intensive therapy caused a 1% fall in HbA1c and was associated with a 35% reduction in microvascular endpoints (though most of the benefit was attributable to a decreased need to use photocoagulation for retinopathy)
- Metformin (but not sulfonylurea or insulin) decreased mortality independent of blood sugar control
- Tight BP control in diabetics reduced mortality
How is HbA1c formed?
- Glucose irreversibly attaches to hemoglobin at a rate dependent on blood glucose.
What does HbA1c indirectly measure?
- The patient’s average glucose level over the preceding 120 days (the life span of RBCs), although it best correlates with average blood glucose over 56-84 days
What will falsely elevate HbA1c?
- Any process that decreases RBC turnover (eg, vitamin B 12 , folate, or iron deficiency)
What will falsely decrease HbA1c?
Any process that decreases RBC turnover (eg, vitamin B 12 , folate, or iron deficiency)
How frequently should HbA1c be checked?
- Every 3-4 months until at goal, then every 6 months
What is the goal for HbA1c?
HbA1c <7% (an average blood glucose of 154 mg/dL)
What is the treatment for type I DM?
- Insulin replacement
What are the treatments for type II DM?
- Weight loss
- exercise
- Diet
- oral hypoglycemic medications
- exogenous insulin
Defination of a metabolic syndrome
Any three of the following:
- Abdominal obesity (waist circumference in men >40 in, women >35 in)
- Serum triglycerides ≥150 mg/dL or drug treatment for elevated triglycerides
- Serum high-density lipoprotein (HDL) cholesterol <40 mg/dL in men and <50 mg/dL in women or drug treatment for low HDL
- BP ≥130/85 mm Hg or drug treatment for elevated BP
- Fasting plasma glucose (FPG) ≥100 mg/dL or drug treatment for elevated blood glucose
What are the clinical implications of having the metabolic syndrome?
Increased risk of developing diabetes and cardiovascular disease
What is the body mass index (BMI) measurement?
An indirect approximation of body fat
How is BMI calculated?
- ([Weight in lbs.]/[height in in.] 2 ) × 703 or
- (Weight in kgs.)/(height in m.) 2
Which BMI level represents being overweight?
Between 25 and 29.9
Which BMI level represents being obese?
≥30
In what situation does BMI overestimate body fat?
A person with a higher than average percentage of muscle mass
Which diseases of the exocrine pancreas can cause diabetes?
- Cystic fibrosis
- hemochromatosis
- chronic pancreatitis
Which endocrinopathies can cause diabetes?
- Any increase in hormones that inhibit insulin:
- Cushing (cortisol)
- glucagonoma (glucagon)
- pheochromocytoma (epinephrine)
- acromegaly (growth hormone)
What is diabetic ketoacidosis (DKA)?
- A medical emergency where insulin deficiency leads to hyperglycemia, electrolyte disturbances, ketonemia, and metabolic acidosis
How does the insulin deficiency precipitate DKA?
- In insulin deficiency, the liver breaks down lipids into ketone bodies resulting in a decrease in blood pH (serum ketones + acidosis).
What can precipitate DKA? .
- I’s: I nfection,
- I nfarction (cardiac, cerebral, mesenteric),
- I nsulin (prescription dose is too low, patient is noncompliant),
- I ntraabdominal process (pancreatitis),
- I ntoxication (alcohol),
- I diopathic. Also consider physical stress and drugs (eg, glucocorticoids, second-generation antipsychotics)
How do you categorize the acid-base abnormality in DKA?
Anion gap metabolic acidosis with compensatory respiratory alkalosis
What is Kussmaul breathing?
Rapid, deep breathing to help increase CO 2 excretion and correct the underlying acidosis in DKA
A patient with DKA can have what odor to their breath?
- Fruity, acetone odor
What is the treatment of DKA?
- Aggressive IV fluids
- IV insulin
- acid-base and electrolyte management (potassium, phosphorus)
When can you transition the patient from IV insulin to subcutaneous insulin?
- When the anion gap has resolved and the bicarbonate level approaches normal
What are the diagnostic criteria for hyperosmolar hyperglycemia state (HHS)?
- Plasma glucose >600 mg/dL
- arterial pH >7.3
- serum bicarbonate >18 mEq/L
- effective serum osmolality >320 mOsm/kg
- minimal ketones in serum and urine
How do you manage HHS?
- Aggressive IV fluids
- IV insulin
- correction of electrolyte abnormalities (such as potassium depletion)
- monitoring of urine output and mental status
What percentage of patients with HHS also present with neurologic abnormalities such as coma?
- 25%-50%.
- Neurologic changes occur in patients with effective plasma osmolalities above 320 mOsm/kg.
